--- /dev/null
+/***********************************************************************
+*
+* if.c
+*
+* Implementation of user-space PPPoE redirector for Linux.
+*
+* Functions for opening a raw socket and reading/writing raw Ethernet frames.
+*
+* Copyright (C) 2000 by Roaring Penguin Software Inc.
+*
+* This program may be distributed according to the terms of the GNU
+* General Public License, version 2 or (at your option) any later version.
+*
+***********************************************************************/
+
+static char const RCSID[] =
+"$Id: if.c,v 1.2 2008/06/09 08:34:23 paulus Exp $";
+
+#define _GNU_SOURCE 1
+#include "pppoe.h"
+#include "pppd/pppd.h"
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#ifdef HAVE_NETPACKET_PACKET_H
+#include <netpacket/packet.h>
+#elif defined(HAVE_LINUX_IF_PACKET_H)
+#include <linux/if_packet.h>
+#endif
+
+#ifdef HAVE_ASM_TYPES_H
+#include <asm/types.h>
+#endif
+
+#ifdef HAVE_SYS_IOCTL_H
+#include <sys/ioctl.h>
+#endif
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_NET_IF_ARP_H
+#include <net/if_arp.h>
+#endif
+
+/* Initialize frame types to RFC 2516 values. Some broken peers apparently
+ use different frame types... sigh... */
+
+UINT16_t Eth_PPPOE_Discovery = ETH_PPPOE_DISCOVERY;
+UINT16_t Eth_PPPOE_Session = ETH_PPPOE_SESSION;
+
+/**********************************************************************
+*%FUNCTION: etherType
+*%ARGUMENTS:
+* packet -- a received PPPoE packet
+*%RETURNS:
+* ethernet packet type (see /usr/include/net/ethertypes.h)
+*%DESCRIPTION:
+* Checks the ethernet packet header to determine its type.
+* We should only be receveing DISCOVERY and SESSION types if the BPF
+* is set up correctly. Logs an error if an unexpected type is received.
+* Note that the ethernet type names come from "pppoe.h" and the packet
+* packet structure names use the LINUX dialect to maintain consistency
+* with the rest of this file. See the BSD section of "pppoe.h" for
+* translations of the data structure names.
+***********************************************************************/
+UINT16_t
+etherType(PPPoEPacket *packet)
+{
+ UINT16_t type = (UINT16_t) ntohs(packet->ethHdr.h_proto);
+ if (type != Eth_PPPOE_Discovery && type != Eth_PPPOE_Session) {
+ error("Invalid ether type 0x%x", type);
+ }
+ return type;
+}
+
+/**********************************************************************
+*%FUNCTION: openInterface
+*%ARGUMENTS:
+* ifname -- name of interface
+* type -- Ethernet frame type
+* hwaddr -- if non-NULL, set to the hardware address
+*%RETURNS:
+* A raw socket for talking to the Ethernet card. Exits on error.
+*%DESCRIPTION:
+* Opens a raw Ethernet socket
+***********************************************************************/
+int
+openInterface(char const *ifname, UINT16_t type, unsigned char *hwaddr)
+{
+ int optval=1;
+ int fd;
+ struct ifreq ifr;
+ int domain, stype;
+
+#ifdef HAVE_STRUCT_SOCKADDR_LL
+ struct sockaddr_ll sa;
+#else
+ struct sockaddr sa;
+#endif
+
+ memset(&sa, 0, sizeof(sa));
+
+#ifdef HAVE_STRUCT_SOCKADDR_LL
+ domain = PF_PACKET;
+ stype = SOCK_RAW;
+#else
+ domain = PF_INET;
+ stype = SOCK_PACKET;
+#endif
+
+ if ((fd = socket(domain, stype, htons(type))) < 0) {
+ /* Give a more helpful message for the common error case */
+ if (errno == EPERM) {
+ fatal("Cannot create raw socket -- pppoe must be run as root.");
+ }
+ error("Can't open socket for pppoe: %m");
+ return -1;
+ }
+
+ if (setsockopt(fd, SOL_SOCKET, SO_BROADCAST, &optval, sizeof(optval)) < 0) {
+ error("Can't set socket options for pppoe: %m");
+ close(fd);
+ return -1;
+ }
+
+ /* Fill in hardware address */
+ if (hwaddr) {
+ strlcpy(ifr.ifr_name, ifname, IFNAMSIZ);
+ if (ioctl(fd, SIOCGIFHWADDR, &ifr) < 0) {
+ error("Can't get hardware address for %s: %m", ifname);
+ close(fd);
+ return -1;
+ }
+ memcpy(hwaddr, ifr.ifr_hwaddr.sa_data, ETH_ALEN);
+#ifdef ARPHRD_ETHER
+ if (ifr.ifr_hwaddr.sa_family != ARPHRD_ETHER) {
+ warn("Interface %.16s is not Ethernet", ifname);
+ }
+#endif
+ if (NOT_UNICAST(hwaddr)) {
+ fatal("Can't use interface %.16s: it has broadcast/multicast MAC address",
+ ifname);
+ }
+ }
+
+ /* Sanity check on MTU */
+ strlcpy(ifr.ifr_name, ifname, IFNAMSIZ);
+ if (ioctl(fd, SIOCGIFMTU, &ifr) < 0) {
+ error("Can't get MTU for %s: %m", ifname);
+ } else if (ifr.ifr_mtu < ETH_DATA_LEN) {
+ error("Interface %.16s has MTU of %d -- should be at least %d.",
+ ifname, ifr.ifr_mtu, ETH_DATA_LEN);
+ error("This may cause serious connection problems.");
+ }
+
+#ifdef HAVE_STRUCT_SOCKADDR_LL
+ /* Get interface index */
+ sa.sll_family = AF_PACKET;
+ sa.sll_protocol = htons(type);
+
+ strlcpy(ifr.ifr_name, ifname, IFNAMSIZ);
+ if (ioctl(fd, SIOCGIFINDEX, &ifr) < 0) {
+ error("Could not get interface index for %s: %m", ifname);
+ close(fd);
+ return -1;
+ }
+ sa.sll_ifindex = ifr.ifr_ifindex;
+
+#else
+ strcpy(sa.sa_data, ifname);
+#endif
+
+ /* We're only interested in packets on specified interface */
+ if (bind(fd, (struct sockaddr *) &sa, sizeof(sa)) < 0) {
+ error("Failed to bind to interface %s: %m", ifname);
+ close(fd);
+ return -1;
+ }
+
+ return fd;
+}
+
+
+/***********************************************************************
+*%FUNCTION: sendPacket
+*%ARGUMENTS:
+* sock -- socket to send to
+* pkt -- the packet to transmit
+* size -- size of packet (in bytes)
+*%RETURNS:
+* 0 on success; -1 on failure
+*%DESCRIPTION:
+* Transmits a packet
+***********************************************************************/
+int
+sendPacket(PPPoEConnection *conn, int sock, PPPoEPacket *pkt, int size)
+{
+ int err;
+
+ if (debug)
+ pppoe_log_packet("Send ", pkt);
+#if defined(HAVE_STRUCT_SOCKADDR_LL)
+ err = send(sock, pkt, size, 0);
+#else
+ struct sockaddr sa;
+
+ strcpy(sa.sa_data, conn->ifName);
+ err = sendto(sock, pkt, size, 0, &sa, sizeof(sa));
+#endif
+ if (err < 0) {
+ error("error sending pppoe packet: %m");
+ return -1;
+ }
+ return 0;
+}
+
+/***********************************************************************
+*%FUNCTION: receivePacket
+*%ARGUMENTS:
+* sock -- socket to read from
+* pkt -- place to store the received packet
+* size -- set to size of packet in bytes
+*%RETURNS:
+* >= 0 if all OK; < 0 if error
+*%DESCRIPTION:
+* Receives a packet
+***********************************************************************/
+int
+receivePacket(int sock, PPPoEPacket *pkt, int *size)
+{
+ if ((*size = recv(sock, pkt, sizeof(PPPoEPacket), 0)) < 0) {
+ error("error receiving pppoe packet: %m");
+ return -1;
+ }
+ if (debug)
+ pppoe_log_packet("Recv ", pkt);
+ return 0;
+}
projects / ppp.git / blobdiff